A neon Wi-Fi sign on a wall.
Skorzewiak/Shutterstock.com

The sun produces solar radiation, and we call that “sunlight.” Likewise, Wi-Fi uses radio waves, which are a form of radiation. Despite what some snake oil salesmen may tell you, you don’t need an EMF shield, “router guard,” or “Wi-Fi radiation shield.”

Even if you did want to remove Wi-Fi from your home (and you don’t need to!), you’d be better off switching to a wired router and ditching all your Wi-Fi hardware. Skip the “router cages” and “router covers.”

“Blocking Wi-Fi Radiation” Means “Blocking Wi-Fi”

EMF shields or wireless “router guards” promise to block Wi-Fi radiation. There’s just one problem: “Wi-Fi radiation” just means “Wi-Fi radio waves.”

That’s not new, of course: AM and FM radio also use radio waves, for example. So do walkie-talkies, cordless telephones, wireless baby monitors, and many other common technologies that we’ve lived with for decades.

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Since Wi-Fi is just radio waves (a type of radiation), blocking Wi-Fi radiation just means blocking Wi-Fi. If a router guard promises to “block 85% of Wi-Fi radiation,” that’s just another way of saying that it will make your wireless router operate at 15% efficiency.

Wi-Fi Isn’t Dangerous

Wi-Fi radiation isn’t dangerous to you. We encourage you to read our full explanation of why Wi-Fi radiation isn’t dangerous. In short, the dangerous type of radiation is ionizing radiation—like X-rays. Ionizing radiation has enough energy to “ionize” atoms and other molecules by knocking an electron out of their orbit.

However, Wi-Fi counts as “non-ionizing radiation”—like AM and FM radio. There is no scientific evidence that Wi-Fi radiation is dangerous, just as there’s no evidence that the radio waves used by walkie-talkies (in other words, the radiation produced by walkie-talkies) are dangerous.

RELATED: Don't Worry: Wi-Fi Isn't Dangerous

What Does an EMF Shield or “Router Guard” Do?

A Wi-Fi router cover.
Here it is: A cage for your router. That’ll be $85. Smart Meter Covers

These devices are a type of Faraday cage that you place around your router. A Faraday cage is an enclosure that blocks electromagnetic fields. That’s why it’s called an “EMF shield”—it functions as a shield against electromagnetic fields (EMFs).

This is a fancy way of saying that a “router guard” that you place around your router just interferes with the Wi-Fi signal, either weakening it dramatically or blocking it entirely.

Why would someone want to do this? Well, if they believed that Wi-Fi was dangerous, such a device might be valuable! But knowing that Wi-Fi isn’t dangerous, we see that there is little point to such a device.

Such devices are unfortunately being widely advertised online, including on Amazon. While we definitely believe in the right of everyone to buy these kinds of products if they want them—that’s freedom, after all—we think you should know that these products are a waste of your money. Even if you believe the premise that Wi-Fi is dangerous, these Wi-Fi shields don’t make much sense.

Again, Wi-Fi Is Just Radio Waves, Which Are Radiation

Wi-Fi is just radio waves, and radio waves are a type of radiation. A Wi-Fi router uses electromagnetic frequencies, also known as “radio waves” or “Wi-Fi radiation,” to communicate with your devices and give them access to the internet. That’s all it does.

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Operating a Wi-Fi router and placing it in a Faraday cage is like setting up a radio broadcast tower and enclosing it in a cage that prevents people from receiving its signal. It doesn’t make any sense.

If the Router Guard Works, It Makes Your Wi-Fi Worse

If you look at the reviews for such devices on Amazon, you’ll see many people leaving one-star reviews complaining that the Wi-Fi shield made their WI-Fi worse. Perhaps it now only works in the same room as the Wi-Fi router, when without the Faraday cage, the Wi-Fi offers a strong signal in every room in their home.

That’s by design. That’s how it works! It works by inhibiting your Wi-Fi signal. Less Wi-Fi radiation escapes the cage, which means that your Wi-Fi is weaker.

But Some Router Guards Promise Strong Wi-Fi!

If you click around and look at these products, you’ll find that some router guards promise not to interfere with your Wi-Fi. They promise to reduce Wi-Fi radiation while giving you a strong signal. Some products might even have reviews saying, “This product works, unlike other router guards that made my Wi-Fi worse!”

How can this be?

Well, perhaps the manufacturer is lying and the router guard will actually make your Wi-Fi worse once you set it up.

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However, if a particular router guard doesn’t interfere with your Wi-Fi signal at all,ย that means that it isn’t doing anything. It’s not actually blocking radio waves (radiation) if it doesn’t have any effect on your signal.

Perhaps one Wi-Fi EMF shield interferes less with Wi-Fi than another one. That just means that the radiation shield that gives you a better Wi-Fi signal is blocking less Wi-Fi radiation than the one giving you a weaker signal, which is blocking more Wi-Fi radiation.

There’s no free lunch. Wi-Fi is radio waves, which are radiation. Blocking Wi-Fi radiation means blocking your Wi-Fi signal. If you could block 100% of Wi-Fi radiation, you’d make your Wi-Fi router 100% useless.

Try Wired Internet If You Don’t Want Wi-Fi

Even if Wi-Fi radiation were a concern—and we’re not saying it is—a Wi-Fi EMF shield or “router guard” wouldn’t make any sense as a product.

There are several options. Either you have an ineffective shield that gives you good Wi-Fi because it isn’t actually blocking anything, an effective EMF shield that is so good that it prevents you from using Wi-Fi, or a shield that’s somewhere in the middle, giving you a weak WI-Fi signal but still allowing some of that “Wi-Fi radiation” (in other words, the Wi-Fi signal) to escape the cage.

If you were concerned about this, you could ditch the Wi-Fi router and get a wired router where you connect your computers and other devices with Ethernet cables instead. You could then avoid using Wi-Fi and prevent your router from emitting any “Wi-Fi radiation” (in other words, Wi-Fi signal).

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But you don’t need to do any of this, because Wi-Fi isn’t dangerous.

Or Try the National Radio Quiet Zone

The Robert C. Byrd Green Bank Telescope
The Robert C. Byrd Green Bank Telescope listens for radio signals from deep space in Green Bank, West Virginia. John M. Chase/Shutterstock.com

Even if you didn’t use your own Wi-Fi router, you would still be exposed to other forms of radio waves (radiation).ย For example, this includes Wi-Fi signals from your neighbors, cell phone signals, Bluetooth device communications, FM radio, AM radio, walkie-talkie signals, cordless phones, wireless baby monitors, and so on.

In the U.S., a good way to avoid a lot of this would be to move to the U.S. National Radio Quiet Zone, a place in the country where most types of EMF radiation (including Wi-Fi and cell phone signals) are restricted to reduce disturbances to sensitive equipment used for scientific research and military intelligence gathering in the area.

Of course, you don’t need to move there—because there’s no evidence that these types of radiation are dangerous.

But if you did believe that radio waves were a problem, a router shield wouldn’t be a good solution, because you’d only be dealing with a small part of the problem. (But again, it’s not a problem!)


One last thing: 5G is also just radio waves, and there’s no evidence that it’s dangerous either.

RELATED: How Worried Should You Be About the Health Risks of 5G?

Profile Photo for Chris Hoffman Chris Hoffman
Chris Hoffman is Editor-in-Chief of How-To Geek. He's written about technology for over a decade and was a PCWorld columnist for two years. Chris has written for The New York Times, been interviewed as a technology expert on TV stations like Miami's NBC 6, and had his work covered by news outlets like the BBC. Since 2011, Chris has written over 2,000 articles that have been read nearly one billion times---and that's just here at How-To Geek.
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